Abstract : TACOS 2 was originally developed for use in direct support of the USACDCADA SAM-D Weapons Family Cost-Effectiveness Study (SAMWEPS). The major development cycle expended approximately 50 man-months over the period October 1966 to May 1967. Improvements and changes have been constantly made to TACOS 2 to encompass dynamic threat and defense concepts. The usefulness of TACOS 2 was enhanced when it was converted for use on a CDC 6600 by the U.S. Army Missile Command (MICOM) in 1971. It is this enhanced version which is described in this document. The total simulation is composed of three major parts or FRAG's, each of which is one or more separate programs. These FRAG's are described in the report.